Through the disappointment, Andy Murray knew that reaching a grand slam quarter-final four months after being unable to walk was a positive result.

The Scot's run at the Australian Open was brought to an end on Wednesday night with a four-set defeat by a rejuvenated Roger Federer.

Murray was playing in only his second tournament after undergoing surgery for a long-standing back complaint in September.

From being confined to his bed, Murray gradually increased his rehabilitation and trained in Miami from mid-November right up until his first outing of the new season in Abu Dhabi at the end of last month.

Although the 26-year-old went into the tournament unsure of how he would fare, the effort he had put in just to be in Melbourne in some ways heightened his disappointment.

Murray said: "It's frustrating because it's basically been four months from when you're lying on your back not being able to move or walk. You put in a lot of hard work for this long period.

"Then, as much as you haven't played enough matches and stuff, a lot of work and time goes into getting yourself ready. You want to give yourself the best chance to win.

"A lot of work went into this slam compared with other ones where you have a few weeks to prepare. This time I had a long time to prepare, maybe just not enough matches."

Federer outplayed Murray for the best part of three sets, his renewed confidence shining through in a display of attacking tennis reminiscent of his glory years.

The Swiss served for the match at 5-4 in the third set but Murray broke back and then saved two match points on his way to winning the tie-break.

But Murray's lack of stamina showed in the fourth set, and the second time Federer served for the victory he made no mistake.

"I was proud of the way I fought," said Murray.

"That's the highest level I've played at in a long time. My serve slowed down a bit in the fourth set, especially the first couple of points when I was getting up after the change of ends.

"But I hung in well. I pushed through it and almost got myself back in the match."

Federer goes through to a 33rd meeting with his old foe Rafael Nadal and is looking to reach his first grand slam final since beating Murray to win Wimbledon in 2012.

Federer's miserable 2013 was exacerbated by his own back problems, and it has been key to his progress in Melbourne that the 32-year-old was able to train fully during the off season.

"I guess I know exactly what he's going through, because that's how I felt because you couldn't work out sometimes," he said.

"You get tired throughout the match. It's just not a good feeling to have because you start doubting yourself and then things get tough."